Can Unlimited Energy Launch Objects into Orbit Using Accelerator Technology?

• B
• OutOfTheBox
In summary: No, OotB, there are no discussions or concepts being developed related to how an infinite energy source could be used to reduce the amount of fuel required to reach escape velocity.
OutOfTheBox
TL;DR Summary
Trying to understand the factors of a launch concept
If an infinite amount of energy were available to create the lift mechanism for a space launch. What would be required to fire a 200lb object into low Earth orbit(160km) after speeding it up in a way similar to how the large hadron collider speeds up a particle.

Assuming the launch vehicle would:
A. Use technology x to protect its cargo from the effects of the G-force's it would be exposed to
B. Have a drag coefficient of 0.04
C. Have no additional propulsion after launch
D. Launch at sea level

The first questions I am looking to understand include:
1. Trajectory wise, is it more efficient to launch the object perpendicular to the Earth's surface like a rocket or at an angle like a ramp?
2. what is the minimum speed the object needs to be going when it leaves the Earth's surface to reach low Earth orbit unassisted?

Any trajectory you put it in will come from the atmosphere. If it isn't moving at escape velocity at the time it exits the atmosphere, it will come back and go through re-entry regardless of trajectory. It cannot reach LEO unassisted.

sophiecentaur
This is called a space gun. Without additional propulsion to correct the course the object will either fall back to Earth or keep going for ever.

russ_watters and sophiecentaur
Passing from the Earth's surface through the atmosphere will be difficult. If the velocity is sufficient to escape to LOE, then the object will be destroyed by the high temperatures normally only seen during re-entry.

A rocket launch to LEO does not accelerate to escape velocity until it is above most of the atmosphere. “Go with throttles up” signifies that point where it is safe to accelerate.

sophiecentaur and berkeman
OutOfTheBox said:
Summary:: Trying to understand the factors of a launch concept

If an infinite amount of energy were available to create the lift mechanism for a space launch.
Seriously not the best way to start thinking about a launch system. We don't have any energy (money) to spare for that sort of exercise. The same basic method has been used for launches since the fifties - with good reason. It's already been pointed out that escaping without an extra manoeuvre just doesn't work.
The term "escape velocity" is only a convenient number for comparing the situations on different planets.
Also, it's fair to say that we have never had enough fuel and a big enough rocket system to 'escape' the solar system; we have always needed to use slingshot orbits to help us get anywhere interesting beyond our nearest neighbours.

sophiecentaur said:
OutOfTheBox said:
If an infinite amount of energy were available to create the lift mechanism for a space launch.
Seriously not the best way to start thinking about a launch system. We don't have any energy (money) to spare for that sort of exercise.
Is it possible, OotB, that this is part of a story you're developing? (There's a forum for that.)

DaveC426913 said:
Is it possible, OotB, that this is part of a story you're developing? (There's a forum for that.)
Jules Verne was there first, I believe.

Thank you all I am now reading more into the "Space Gun" concept.

Continuing on from the original concept, are there discussions or concepts being developed related to how an infinite energy source could be used to reduce the amount of fuel required to reach escape velocity?

OutOfTheBox said:
Thank you all I am now reading more into the "Space Gun" concept.

Continuing on from the original concept, are there discussions or concepts being developed related to how an infinite energy source could be used to reduce the amount of fuel required to reach escape velocity?
I believe that infinite energy sources tend to be quite fuel inefficient.

phinds
PeroK said:
I believe that infinite energy sources tend to be quite fuel inefficient.
How would you know? The gauge would always read ∞

Imager, DaveC426913, Vanadium 50 and 1 other person
Would the best use of that infinite energy be to use it to produce hydrogen fuel and use the launch methods already derived?

Infinite energy would entail infinite mass, which would prevent anything from getting into orbit at all.
Perhaps you mean just free energy, in which case you'd have to work out exactly what isn't free and find a solution that makes the most efficient use of those more limited resources.

OutOfTheBox said:
Would the best use of that infinite energy be to use it to produce hydrogen fuel and use the launch methods already derived?
You really need to drop the concept of "infinite" energy since it doesn't exist. If you mean "however much energy is required to do ... " then say THAT, not "infinite" energy. This is a science forum and words have meaning.

davenn, Bystander and sophiecentaur
OutOfTheBox said:
are there discussions or concepts being developed related to how an infinite energy source could be used to reduce the amount of fuel required to reach escape velocity?

You are asking "If we had unlimited energy, could it be used to reduce the amount of energy required?"

Sortta like:
"My house is powered by the flow of water over Niagara Falls. Could I utilize more energy from Niagara Falls to reduce the energy that it takes Niagara Falls to power my house?"

Bystander and PeroK
I should not use the word energy or infinite energy it is just how it is referred to in some papers I am reading. Perhaps the correct word would be power. i.e. electrical current.

Meaning an infinite store of electrical current, such that could result from breakthroughs in fusion.

Would this be the correct reference?

No. Please stop using the word "infinite" and we're good.

phinds, DaveC426913 and Bystander
The most efficient way to rise through the atmosphere is vertically, but then the least energy to enter orbit is to accelerate towards the east above the equator, taking advantage of Earth's rotation. On reaching an altitude above most of the atmosphere, say 10 km, you must find a way to convert a vertical velocity of mach 2 into an eastward mach 20. That will require energy be stored in some other convertible form. If you started on the surface with mach 40, you might have 20 left after passage through the lower atmosphere. But most of the object would have been vaporised like a meteorite in the process.

Alternatively you must revise your constraints.

The “all velocity up-front” technique you are suggesting might work from the moon where there is no atmosphere, but it is not possible from the Earth. On the Moon, a solar-powered linear-motor track could accelerate the mass, but the orbit it would enter would be an ellipse that returns to the launch track, unless there was some thrust control to convert the elliptical orbit into a more circular lunar orbit.

gmax137 and OutOfTheBox
OK, here's any alternative approach to the OP question. What if we had ridiculous amounts of energy available and we could use it to get things into orbit in not so much a very efficient or quick way but in a way that was convenient / a nice experience / very safe. It could involve a vast capital project (affordable, for the first time in our history)?
All that energy would probably make a space elevator feasible. That ticks all the boxes. So take-off would take several (tens of?) hours to achieve but it could involve some luxurious lifestyle whilst you are aboard the trip. Vast space ships (starships?) could be assembled up there for long distance journeys, taking generations.
SciFi material, too.

Bystander and hutchphd
You could always use your infinite energy to compress the Earth's atmosphere into some massive underground holding tanks that you excavated using your infinite energy and then lined with steel smelted with your infinite energy.

Then use your space-gun to launch as many craft as you like without worrying about air resistance.

berkeman, Bystander and DaveC426913
OutOfTheBox said:
I should not use the word energy or infinite energy it is just how it is referred to in some papers I am reading.
This is a red flag. It makes me want to tell you you should stop reading those papers. They are probably doing you more harm than good.

OutOfTheBox said:
Perhaps the correct word would be power. i.e. electrical current.
It doesn't matter. Energy/fuel or whatever. We assume they can be converted without needing details.

OutOfTheBox said:
Meaning an infinite store of electrical current, such that could result from breakthroughs in fusion.
At least restrain yourself to the term 'unlimited'? But I still don't see what your question is.

Look. given an unlimited supply of energy, you don't need to think about launch methods. It's moot.
For all you care, you can just have your space cruiser (not rocket) lift straight off its wheels from the spaceport tarmack - horizontal, and
rising at a leisurely 100ft a minute (for sight-seers) - all the way to space.

Furthermore, since you have unlimited energy,
there is no reason to power up to orbital velocity at all.

(The only reason to reach orbital velocity is so you can shut off your engines and not die in a fireball. And that's only because - with our current technology - we have a very limited supply of energy in our vehicles and must reach orbit before it runs out.)

With unlimited energy, you don't care one wit about orbital velocity. You could, at your leisure, make a circumnavigation of the Earth at
a scenic 1,000 miles per hour (to follow the sunrise perhaps) and then just turn and head for the Moon at the same leisurely 1,000 miles per hour, giving your tourists a two week cruise.

Unlimited energy renders virtually all aspects of orbital mechanics moot. And that includes re-entry - you could come down as slow as you like.
At a gentle 300 miles per hour, there's no re-entry fireball.

Unlimited energy changes everything.

Last edited:
phinds, sophiecentaur, Bystander and 1 other person
DaveC426913 said:
Unlimited energy changes everything.
Except the OP constraints; C and D; that required all the energy be invested before departure from the surface below the atmosphere.
OutOfTheBox said:
Assuming the launch vehicle would:
A. Use technology x to protect its cargo from the effects of the G-force's it would be exposed to
B. Have a drag coefficient of 0.04
C. Have no additional propulsion after launch
D. Launch at sea level

DaveC426913
Baluncore said:
Except the OP constraints; C and D; that required all the energy be invested before departure from the surface below the atmosphere.
Right. Well.

You're either headed for deep space real soon, or you're headed for some litho-braking real soon.

OutOfTheBox said:
Summary:: Trying to understand the factors of a launch concept

If an infinite amount of energy were available to create the lift mechanism for a space launch. What would be required to fire a 200lb object into low Earth orbit(160km) after speeding it up in a way similar to how the large hadron collider speeds up a particle.

Assuming the launch vehicle would:
A. Use technology x to protect its cargo from the effects of the G-force's it would be exposed to
B. Have a drag coefficient of 0.04
C. Have no additional propulsion after launch
D. Launch at sea level
It is not out of the box thinking until you do some basic calculations. Fortunately, the calculations are simple enough that only high school physics is needed.

1) Forget your assumption #1. That's science fiction.

2) Change infinite energy to as much power as needed, as discussed above.

3) If you want to accelerate in a circle, then assume a diameter, and calculate the centrifugal acceleration and force at standard escape velocity. How strong does your object need to be? It needs to withstand centrifugal forces while spinning up. You may want to try different diameters. Assume an angular acceleration, and calculate the tangential acceleration and peak power.

4) Calculate the necessary initial velocity including the effects of aerodynamic drag. Use your Cd, assume a frontal area, assume a standard atmosphere, and calculate the aerodynamic drag. This will be a numerical simulation because the aerodynamic drag decreases with increasing altitude. Iterate the initial velocity until it reaches orbit. Now go back and repeat the calculations in Step 3 at the higher velocity. It needs to withstand centrifugal forces while spinning up, and aerodynamic forces after release. How strong does the object need to be? Bonus points if you search hypersonic drag coefficients, and add the effect of velocity on drag to the simulation.

jrmichler said:
1) Forget your assumption #1. That's science fiction.
Technology X is science, but not necessarily fiction.
Remove air or gas by saturating the cargo, and filling the area around the cargo, with a neutral density fluid. The cargo will then be subjected to 3D hydrostatic pressure rather than to 1D acceleration forces.

DaveC426913 said:
Unlimited energy renders virtually all aspects of orbital mechanics moot. And that includes re-entry - you could come down as slow as you like. At a gentle 300 miles per hour, there's no re-entry fireball.
I suggested long-glide re-entry, as opposed to the present system, some while ago. It was jumped on pretty quick by PF! The orbital energy has to be dissipated, one way or another and doing it slowly means that the insides will get too hot and fry the passengers. The fireball / ablative braking system gives a short slow down time and then cools the craft in air before the internal temperature gets too high. It's a race against time to save passenger fry-up, apparently.
Active re-entry systems would avoid the friction problem and use a lot of fuel but that could be taken care of by our unlimited fuel, I guess.

sophiecentaur said:
I suggested long-glide re-entry, as opposed to the present system, some while ago. It was jumped on pretty quick by PF! The orbital energy has to be dissipated, one way or another and doing it slowly means that the insides will get too hot and fry the passengers. The fireball / ablative braking system gives a short slow down time and then cools the craft in air before the internal temperature gets too high. It's a race against time to save passenger fry-up, apparently.
Interesting. Hadn't thought of that.

sophiecentaur said:
Active re-entry systems would avoid the friction problem and use a lot of fuel but that could be taken care of by our unlimited fuel, I guess.
(It's off-topic with the OP's proviso that the craft have no propulsion, but...) Yeah, with the OP's unlimited energy, aerobraking is moot. You can simply brake down to 300mph while still in space. And then leisurely descend to the tarmac like an airplane under power (gliding is so passé).

DaveC426913 said:
You can simply brake down to 300mph while still in space.
Nor really. At such low speeds you will have no lift in the thin atmosphere and would be plummeting, gaining loads of KE again. If you use braking then whatever is slowing you down has to be dissipating a lot of energy and there's very little cooling available in a near vacuum.
I have not done the sums ever but I think we can safely say that it would have been tried long ago for re-entering Earth if it were remotely practical.
I suppose that a truly massive parachute might be an option. The cost would not be a problem in our new scenario, though.

sophiecentaur said:
If you use braking then whatever is slowing you down has to be dissipating a lot of energy and there's very little cooling available in a near vacuum.
We have unlimited energy available, so we rocket-brake. We are shooting all the energy out the back of the vessel to slow down.

bob012345 and sophiecentaur
Adjustable vanes on the bullet could get you a circular "orbit" at 100km... don't know if it'd make it all the way 'round the planet even once, though.

If I had unlimited energy available, I would just bring the desired planets/stars to me instead of sending a spaceship. It's a silly idea.

sophiecentaur and DaveC426913
sophiecentaur said:
Seriously not the best way to start thinking about a launch system. We don't have any energy (money) to spare for that sort of exercise.
Isn't that why it was specified - so the first answer isn't "can't be done, energy/money"?

OutOfTheBox said:
Summary:: Trying to understand the factors of a launch concept

If an infinite amount of energy were available to create the lift mechanism for a space launch. What would be required to fire a 200lb object into low Earth orbit(160km) after speeding it up in a way similar to how the large hadron collider speeds up a particle.

Assuming the launch vehicle would:
A. Use technology x to protect its cargo from the effects of the G-force's it would be exposed to
B. Have a drag coefficient of 0.04
C. Have no additional propulsion after launch
D. Launch at sea level

The first questions I am looking to understand include:
1. Trajectory wise, is it more efficient to launch the object perpendicular to the Earth's surface like a rocket or at an angle like a ramp?
2. what is the minimum speed the object needs to be going when it leaves the Earth's surface to reach low Earth orbit unassisted?
This concept has been explored in detail not for Earth launch because of the atmosphere, but for lunar launch of material for building large space structures. Not a space gun but an electromagnetic launcher called a Mass Driver. In that case high gee forces are not an issue because humans are not being launched and there are no drag forces. Physicist Gerard K. O'Neill developed the concept in the 1970's to support his vision of building large space colonies. It is interesting that his background was accelerator physics. Solar energy can be used which qualifies as unlimited.

https://en.wikipedia.org/wiki/Mass_driver#:~:text=A mass driver or electromagnetic,by electricity to make electromagnets.

Last edited:
anorlunda
bob012345 said:
This concept has been explored in detail not for Earth launch because of the atmosphere, but for lunar launch of material for building large space structures. Not a space gun but an electromagnetic launcher called a Mass Driver. In that case high gee forces are not an issue because humans are not being launched and there are no drag forces. Physicist Gerard K. O'Neill developed the concept in the 1970's to support his vision of building large space colonies. It is interesting that his background was accelerator physics. Solar energy can be used which qualifies as unlimited.

https://en.wikipedia.org/wiki/Mass_driver#:~:text=A mass driver or electromagnetic,by electricity to make electromagnets.
Thank you.

bob012345

1. What is untraditional space travel?

Untraditional space travel refers to any method of traveling through space that does not involve traditional spacecraft or rockets. This can include concepts such as using solar sails, nuclear propulsion, or even teleportation.

2. Is untraditional space travel possible?

While some concepts of untraditional space travel are still in the theoretical stage, there have been successful demonstrations of certain methods such as solar sails and ion propulsion. With advancements in technology, it is possible that more methods will become feasible in the future.

3. How does untraditional space travel differ from traditional space travel?

Untraditional space travel often involves more experimental or unconventional methods compared to traditional space travel, which relies on rockets and established technology. Untraditional space travel also aims to reduce costs and increase efficiency in space travel.

4. What are the potential benefits of untraditional space travel?

Untraditional space travel has the potential to greatly reduce the cost and time of space travel, making it more accessible for scientific research and commercial purposes. It also has the potential to open up new possibilities for exploration and colonization of other planets.

5. What are the risks associated with untraditional space travel?

As with any new technology, there are risks associated with untraditional space travel, such as technical failures, safety concerns, and potential impacts on the environment. Extensive testing and research are necessary to mitigate these risks and ensure the safety of space travelers.

• Sci-Fi Writing and World Building
Replies
4
Views
2K
• Other Physics Topics
Replies
19
Views
3K
• Atomic and Condensed Matter
Replies
2
Views
2K
• Special and General Relativity
Replies
56
Views
5K
• Astronomy and Astrophysics
Replies
9
Views
2K
• Special and General Relativity
Replies
2
Views
691
• Other Physics Topics
Replies
5
Views
1K
• Astronomy and Astrophysics
Replies
85
Views
7K
• Classical Physics
Replies
86
Views
4K
• Aerospace Engineering
Replies
4
Views
3K